RJ's Beginner Guide to Vents, Fans and Furnace   
 

AC Units, Vents, Fans and Furnace

Most fifth-wheel RVs come with two or three air conditioners (AC's), and each AC has its own thermostat that you can operate independently. These thermostats usually offer several modes, such as high and low fan settings, high and low AC settings, automatic AC, and heat mode. Be sure to select the right setting for your needs.

Also keep in mind that only one thermostat will control your furnace and typically it's the center thermostat that manages both the furnace and the center AC unit.

 

AC Maintainance

The AC unit pulls in the warm, humid air from inside the rig and circulates it through evaporator coils before pushing it back into the living space. While doing that, filters catch pollen and dust particles so they don't damage the AC unit.

I recommend that you check your AC filters at least once a month and clean them if they're dirty. There are a few different ways to do this: take out the filters, blow air from the top down to push the dirt particles out, use a vacuum cleaner to suck the dirt out, or gently run it under the sink then tap them dry. Just make sure they're completely dry before reinstalling them on your AC unit. If you do a lot of cooking in your RV, the AC unit in the kitchen is probably going to be the dirtiest one and will need to be serviced more regularly than the other units.

 

Servicing your coils should be done every six months, and it's best to do so in the spring and fall. To clean them, you'll need to follow these steps:

1. Get on the roof when it's dry

2. Take off the outer shroud of the AC unit

3. Remove the inner shroud that covers the evaporator coils

4. Using a good coil cleaner, spray into the coil to cleanse the fins

 

You'll notice a hole that goes down into the interior of the rig - make sure to put down a towel so you don't accidentally spray chemicals inside your RV.

 

In addition, always confirm that the thermistor is placed snugly in your coils. It's not uncommon for it to fall out or become dislodged when removing the shrouds or when your rig gets jostled around as you drive down the road.

 

If the thermistor in your coils isn't working, you could have a few problems. For example, if you're asking for cold air but no cold air is coming out and then you find an ice block on the roof, this may be indicative of a problem with the thermistor. If there's also a lot of humidity in the air outside and water starts dripping from your AC unit into your rig, that's another good sign that something Is wrong with either the thermistor or there's an issue with airflow somewhere.

 

The next step is to remove the shroud inside your rig. There should be four screws holding the plastic shroud in place. Once you have removed those, take a look at the positioning of your divider plate. On one side, warm air comes in and then on the other side of the divider plate, colder air gets pushed out. From time to time due to vibration from driving, the divider plate could move over. If it does happen to move over, we could have warmer air mixing with cold air or vice versa which will limit unit's ability reach its set-point and function properly.

 

RJ's Pro Tip

To avoid future issues with the divider plate, I recommend securing it in place with aluminum tape. This should be a one-time fix, but I still suggest taking a look at this area once yearly to ensure that the tape hasn't come loose and everything is still secure. That way, you can rest assured knowing that the divider plate is staying put.

 

I would also not recommend adding any extra air filters to your AC unit as it will reduce airflow and cause your AC to work harder, which may shorten the lifespan of the machine. If you need improved air quality in your rig, I suggest investing in a separate filtration system instead of relying on the AC unit alone.

 

Early on, you should get up on your RV's roof and take pictures of each AC unit's serial and model numbers. They're usually just stickers, but it's best to do this before they fall off or get dirty. Keep the copies in a safe place so that, if any questions or issues arise down the road, you'll have everything you need to get the right parts and service.

 

Vent Fans

Most RVs have at least one 12V Vent Fan, which is usually located in either the kitchen or bathroom. Some models also come with a rain sensor installed. The way it works is that when you turn on your fan, the upper shroud will pivot and open up. There's a small rain sensor located in the corner of this opening, and if any water droplets hit it, the shroud will automatically close. I recommend that you purchase and install a roof vent cover that goes over your entire vent shroud on the roof. This will come in handy if you're taking a shower or using the bathroom and need the vent fan open, but it starts to rain--the cover will protect against any rain coming in and allow you to keep venting out the air. This is a cheap upgrade that every unit should already have installed, but if yours doesn't, it's still easy to install and makes using your vents more convenient. Roof Vent Covers also protect against hail storms- which I know from experience can be pretty scary if you don't have covers in place, creating double protection. I was fortunate that the vent shroud didn't break, but the next day I ordered Roof Vent Covers to avoid a repeat situation.

 

Maintaining the fans is straightforward--whenever you see that they're dirty, give them a cleaning. To clean the vent fan system:

1) Pull down each of the little locking tabs and turn them to release;

2) With all four locks disengaged, the screen can pop out;

3) Loosen up the fan shaft collar with an Allen wrench so you can remove and wash (with soap and water) the blades

4) wipe down/clean out any dust in surrounding areas; 5). reassemble entirely and you're good to go.

 

RV Furnace

RV furnaces are designed to heat more than just the living area they also heat the storage bays down below. All furnaces use propane and the way the firing sequence works, it will start the fan first. So if you put your hand by the duct you're going to first feel cold air for 15-20 seconds. And that is the normal operating system. If it cycles two or three times turning on blowing cold air and then turn it off and then eventually shuts off and no hot air have been pushed out that's a good indication you are likely out of propane. The furnace needs to have a higher pressure coming from the tank in order to work properly so you may find in certain instances where you can turn on the stove and it works perfectly fine but there may not be enough pressure to sustain the furnace.

 

RJ's Pro Tip

If your rig has two propane tanks, use one until it is emptied. This gives you an idea of how long each tank lasts and allows you to get the second tank refilled before needing it. This way you'll never have to leave your cozy RV in the middle of the cold night to buy more propane.

 

Thermostat

If the screen on your thermostat is not turning on, check the fuse on the backside. If the fuse is fine, you might have to deep dive into other electrical issues. If you need heat and the fuse in your thermostat has blown, consider taking the fuse from another thermostat to get through the night.